/* ==========================================================================
   Back to Top — tombol bulat mengambang, muncul halus setelah scroll turun
   beberapa layar, klik untuk scroll halus ke atas. Warna sama dgn .cta__btn
   (latar gold, ikon ink-darkest) supaya konsisten dgn tombol CTA lain.
   ========================================================================== */

.back-to-top {
  position: fixed;
  left: 24px;
  bottom: 24px;
  z-index: 60;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border: 1px solid var(--gold);
  border-radius: 50%;
  background: var(--gold);
  color: var(--ink-darkest);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.3s ease, transform 0.3s ease, background-color 0.3s ease, border-color 0.3s ease;
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover,
.back-to-top:focus-visible {
  background: var(--gold-dark);
  border-color: var(--gold-dark);
}

.back-to-top:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 2px;
}

.back-to-top i {
  font-size: 22px;
  line-height: 1;
}

@media (max-width: 600px) {
  .back-to-top {
    left: 16px;
    bottom: 16px;
    width: 42px;
    height: 42px;
  }

  .back-to-top i {
    font-size: 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .back-to-top {
    transition: opacity 0.15s linear, visibility 0.15s linear;
    transform: none;
  }
}